ABSTRACT
Hepatitis B virus core antigen (HBc) with the insertion of four external domains of the influenza A M2 protein (HBc/4M2e) form virus-like particles whose structure was studied using a combination of molecular modeling and cryo-electron microscopy (cryo-EM). It was also shown that self-assembling of the particles occurs inside bacterial cells, but despite the big inner volume of the core shell particle, purified HBc/4M2e contain an insignificant amount of bacterial proteins. It was shown that a fragment of the M2e corresponding to 4M2e insertion is prone to formation of amyloid-like fibrils. However, as the part of the immunodominant loop, M2e insertion does not show a tendency to intermolecular interaction. A full-atomic HBc-4M2e model with the resolution of about 3 Š(3.13 Šfor particles of Т = 4 symmetry, 3.7 Šfor particles of Т = 3 symmetry) was obtained by molecular modeling methods based on cryo-EM data.
Subject(s)
Hepatitis B Core Antigens , Viral Matrix Proteins , Cryoelectron Microscopy , Hepatitis B Core Antigens/chemistry , Hepatitis B virus/chemistry , Models, Molecular , Viral Matrix Proteins/chemistryABSTRACT
Special attention should be given to the safety of drugs prepared from animal products. Industrial production of cytomedines and cytamines includes treatment of organs and tissues from young animals. Studies of preparations by methods recommended by the World Health Organization indicate that this technology guarantees the absence of infectious agents, protooncogenes, nucleic acids, and prion proteins.
Subject(s)
Biological Products/standards , Drug Contamination , Peptides/analysis , Proteins/analysis , Animals , Intercellular Signaling Peptides and Proteins , Nucleic Acids/analysis , Prions/analysisABSTRACT
In chronic experiments on dogs with gastric and esophageal fistulas, the feed-back from the gastro-intestinal tract was found not to play the leading role in the maintenance of continuous nervous excitation underlying the first phase of the gastric secretion.
